Two dimensional conductors are expected to show an improved thermoelectric
performance due the positive effect of quantum confinement on the
thermoelectric power, and the decrease of thermal conductivity by interface
boundary scattering. The recent report of a large increase of the
thermoelectric power in quantum wells of Nb-doped SrTiO3 (STO) seems to be
in agreement with this hypothesis. However, extrinsic effects like the
existence of oxygen vacancies that propagate away from the interface cannot
be ruled out, and the results are far from clear. Here we will show the
thermoelectric properties (electrical conductivity, Seebeck coefficient, and
Hall effect), of epitaxial thin-films of (La,Nb)-doped STO. The films have
been deposited by PLD on different substrates (STO, LAO...) to study the
effect of tensile/compressive stress on the thermoelectric properties of the
system. The oxygen pressure during the deposition was carefully controlled
to tune the amount of oxygen vacancies and to compare with the cation
doping. We have performed a systematic study of the transport properties as
a function of thickness and doping, which along with the effect of stress,
allows to understand the effect of charge density and dimensionality in an
oxide system with promising thermoelectric properties. [1] H. Ohta et al.
Nat. Mat. \textbf{6}, (2007) 129.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.F34.8